Setting mode of communication

ABSTRACT

A method in a communication system is disclosed. In the method a procedure for setting up a communication link between a first user equipment and a second user equipment via a communications network is initiated. Information regarding at least two modes of communication that can be used for communication via the communication link is signalled between the first and second user equipment. An indicator regarding a mode to be used for the communication is also signalled between the first user equipment and the second user equipment. After the signalling steps, a procedure for setting the mode of communication in accordance with the indicator is initiated in at least in one of the user equipment. According to an alternative embodiment signalling for reserving a possibility for at least tow different communication modes occurs between elements of the communication system.

CROSS-REFERENCE AND RELATED APPLICATIONS

This patent application is a continuation application of U.S. patentapplication Ser. No. 11/498,711, filed Aug. 4, 2006, which is acontinuation of U.S. Pat. No. 7,181,202 issued on Feb. 20, 2007 (U.S.patent application Ser. No. 11/498,711 filed on Oct. 10, 2002). Thesubject matter of the previously filed application is herebyincorporated by reference.

BACKGROUND

The disclosure relates to communication systems, and in particular tosetting the mode of communication between two nodes.

A communication system is arranged for provision of communicationconnections between two or more entities such as user terminal equipmentand/or other nodes associated with the system. The communication maycomprise, for example, communication of voice, electronic mail (email)and text messages, multimedia and so on. A communication system mayprovide communication over a fixed line or wireless interface for userterminals or other nodes. An example of systems carrying wirelesscommunication is the public land mobile network (PLMN). An example ofthe fixed line networks is the public switched telephone network (PSTN).

A communication system typically operates in accordance with a givenstandard or specification which sets out what the various elements ofthe system are permitted to do and how that should be achieved. Forexample, the standard or specification may define if the user, or moreprecisely, user equipment or terminal is provided with a circuitswitched (CS) service or a packet switched (PS) service or both.Communication protocols and/or parameters which shall be used for theconnection are also typically defined. For example, the manner howcommunication shall be implemented between the user equipment and theelements of the communication network is typically based on a predefinedcommunication protocol. In other words, a specific set of “rules” onwhich the communication can be based on needs to be defined to enablecommunication by means of the communication system.

Examples of the different standards and/or specifications for wirelesscommunication include, without limiting to these, specifications such asGSM (Global System for Mobile communications), AMPS (American MobilePhone System), DAMPS (Digital AMPS), various GSM based systems such asthe GPRS (General Packet Radio Service). The so called 3^(rd) generation(3G) standards include systems such as the WCDMA (Wideband Code DivisionMultiple Access) based UMTS (Multiple Access in Universal MobileTelecommunications System), IMT 2000 (International MobileTelecommunications system 2000), i-Phone and so on.

In a typical wireless cellular communication system a base station of aradio access network serves user equipment such as mobile stations orsimilar terminal apparatus via a wireless interface. Each of the cellsof the cellular system can be served by an appropriate transceiverapparatus, typically, but not always, referred to as a base station(BS). The base station may be connected to and controlled by acontroller entity. For example, in the GSM radio network a base stationis connected to and controlled by a node referred to as a base stationcontroller (BSC). The BSC node may in turn be connected to andcontrolled by a mobile switching center (MSC), a serving GPRS supportnode (SGSN) or similar facility. It shall be appreciated that thecontroller entities may be provided by means of appropriate serverentities. For example, functions of a MSC may be provided by a MSCserver (MSS).

The communication link between a user equipment and the network, i.e.the so called user-to-network leg is typically controlled by at leastone controller entity. The leg may be controlled e.g. by means of a homeor a visited MSC or a MSS media gateway (MGW). When setting up acommunication path between two user equipment via the communicationnetwork the communication mode of the legs at both ends of the path areset up and synchronised so that a desired mode of communication can beprovided for the users. For example, the calling user may wish to have aspeech connection or a video or other multimedia connection with thecalled user, and the connection is then set up accordingly.

The prior art also suggest a fallback behaviour by means of which a callcan be returned to speech mode in case an attempt to establish amultimedia call fails. By means of this feature a calling user does notneed to know whether the called party supports or wants to receive avideo or other multimedia call, because in this case the call wouldautomatically fall back to a speech call. If the fallback feature is notprovided, the call set-up would then simply fail.

The users may also wish to be able to change e.g. from the speech modeto the multimedia mode during an ongoing call. This is enabled e.g. bymeans of the so called SWAP scheme wherein users can start the calleither with speech or with multimedia, and then swap from speech tomultimedia and vice versa during the call. More particularly, e.g. inthe SWAP scheme the users can swap from speech to multimedia and viceversa by initiating the change at both end legs of the connection. Theswap between modes needs to be accomplished locally at each of the endlegs between the respective mobile stations and the visited mobileswitching centre entities. This is so since in the proposed solution thefixed network leg between the wireless legs may offer a substantiallyconstant 64 kbit/s transmission throughout a call, that is the mode ofthe fixed leg is not changed even if the mode of the legs needs to bechanged.

The inventors have found that the change of the modes may not operatesatisfactorily in the prior art communication systems, and that theusers might wish to obtain an improved solution for the change of modes.For example, if the call is done within a 3GPP (third generationpartnership project) Release 4 split core network architecture i.e. in asystem involving elements such as a MSC Servers (MSS) and Media Gateway(MGW) network elements, the swap procedure requires an in-call bearermodification procedure. This procedure is required to be used in orderto be able to dynamically modify characteristics of a user plane (i.e.the Nb interface) connection (codec) between the MGWs associated withthe connection.

The inventors have found that a multimedia call cannot be started whit aspeech-only mode provided with the current ISUP (ISDN User part)signalling and BICC (Bearer Independent Call Control), and that thecurrent ISUP and BICC do not support switching (“swapping”) betweenspeech and multimedia modes. Consequently, the synchronisation of thepossible swaps at both end legs of the connection is left to the users.The users, for example, need to agree verbally on the swap. Both usersneed then activate manually an appropriate radio channel modificationprocedure at their terminals or even setup a new call in the desiredmode.

SUMMARY

Embodiments of the present invention aim to address one or several ofthe above problems.

According to one aspect, there is provided a method in a communicationsystem, the method comprising:

initiation of a procedure for setting up a communication link between afirst user equipment and a second user equipment via a communicationsnetwork;

signalling between the first user equipment and the second userequipment information regarding at least two modes of communication thatcan be used for communication via the communication link;

signalling between the first user equipment and the second userequipment an indicator regarding a mode to be used for thecommunication; and

initiating in at least in one of the user equipment a procedure forsetting the mode of communication in accordance with the indicator.

According to another aspect, there is provided a communication systemcomprising network apparatus for provision of a communication mediabetween a first user equipment and a second user equipment, thecommunication media consisting of a first leg between the first userequipment and the network apparatus, a second leg between the seconduser equipment and the network apparatus, and an intermediate portionbetween the first and second legs, wherein the mode of communication inat least one of said legs can be controlled by the associated userequipment based on instructions signalled to said user equipment fromthe user equipment associated with the other one of the legs.

According to another aspect, there is provided a user equipment forcommunication via a communication system, comprising means forgenerating and interpreting messages that include information regardingpossible modes of communication available for the user equipment andmeans for controlling the mode that shall be used for communication inaccordance with information included in such a message.

According to another aspect, there is provided a method in acommunication system, comprising:

initiating a procedure for setting up a communication media between atleast two user equipment;

signalling from or to a network element of the communication systeminformation regarding at least two modes of communication, one of themodes being for use in the beginning of the communication and the atleast one other mode being reserved for possible use during thecommunication via the communication media;

signalling from or to said network element an indicator regarding a modeselected among said at least two modes; and

setting the mode of communication in accordance with the indicator.

According to another aspect, there is provided a communication system,said system comprising means for providing a communication media betweenat least two user equipment, and a network element for controlling acommunication leg of said communication media, said leg being providedbetween a user equipment and the communication system, the networkelement being adapted for sending and/or receiving information regardingat least two modes of communication, one of the modes being for use inthe beginning of communication via said communication media and the atleast one other mode being reserved for possible use during thecommunication via the communication media, and also for sending and/orreceiving an indicator regarding a mode selected among said at least twomodes, and for setting the mode of communication in said leg inaccordance with the indicator.

According to another aspect, there is provided a network element for acommunication system, the element being arranged to control acommunication leg provided between a user equipment and thecommunication system, for sending and/or receiving information regardingat least two modes of communication, one of the modes being for use inthe beginning of communication via said communication leg and the atleast one other mode being reserved for possible use during thecommunication via the communication leg, for sending and/or receiving anindicator regarding a mode selected among said at least two modes, andfor setting the mode of communication in said leg in accordance with theindicator.

The embodiments of the invention may provide a solution wherein a videoor other multimedia call can be started in a less demanding i.e. a lowergrade mode such as in the speech mode. The lower grade mode may becheaper to use. A swap to multimedia can be made only when required. Areturn to the cheaper speech mode can be made when the multimedia modeis no longer required. The swap may be automatically synchronised andcontrolled without requiring any activation by the users.

BRIEF DESCRIPTION OF THE DRAWINGS

For better understanding of the disclosure, reference will now be madeby way of example to the accompanying drawings in which:

FIG. 1 is a schematic presentation of a communication system wherein theembodiments of the present invention can be applied to;

FIG. 2 is a flowchart illustrating operation in accordance with oneembodiment;

FIGS. 3 to 5 are signalling flowcharts for various embodiments;

FIG. 6 is a flowchart illustrating operation in accordance with anotherembodiment; and

FIG. 7 shows a further embodiment.

DETAILED DESCRIPTION

Reference is made to schematic FIG. 1 which shows a communication systemwherein the embodiments may be employed. More particularly, FIG. 1 showsa circuit switched PLMN network 10 and two mobile user terminalequipment, i.e. mobile stations MS A and MS B. The operation of atypical PLMN system, such as those based on the GSM, and variouselements thereof is known by the skilled person, and is thus notexplained in any greater detail. It is sufficient to note that each ofthe mobile stations MS A and MS B may communicate over a wirelessinterface with a respective base station BS1, BS2 of the communicationnetwork 10. The communication link or media between mobile stations MS Aand MS B consist of the two wireless interfaces and the intermediatecommunication media within the network 10.

Two controller entities, and more particularly two mobile switchingcentres MSC 1 and 2 are also shown. Each of the mobile switching centres(MSC) may comprise a home MSC or a visited MSC. The MSCs may be providedwith any appropriate controller entity, such as a server or a moreconventional switching entity. The controller entities 1 and 2 are forcontrolling the provision of the wireless communication links for themobile stations MS A and MS B, respectively.

The herein described embodiments are implemented by means of the userterminal equipment MS A and MS B or the apparatus of the communicationnetwork. The following will describe these possibilities, starting fromthe solution wherein the change of the communication mode is initiatedby means of communication between at least two user terminal equipment.

A solution that is based on signalling between the user equipment willbe described first generally with reference also to the flowchart ofFIG. 2.

When a calling user equipment MS A wants the call to start e.g. in thespeech mode, the terminal may reserve a possibility to swap later on toanother mode. For example, the user may wish to reserve a possibility tochange to a UDI/RDI (Unrestricted Digital Information/Restricted DigitalInformation) video/multimedia mode during an already established call.

The calling user terminal equipment MS A may accomplish this by sendingtwo Bearer Capability Information Elements (BCIEs) in a SETUP message(e.g. a GMS/UMTS SETUP message). The BCIEs may comprise a ‘Speech’ BCIEand a ‘UDI/RDI Multimedia’ BCIE. The BCIEs are preferably in the orderthe user of the calling user equipment MS A wishes the call to proceed.For example, the GSM/UMTS SETUP messages are capable of carrying twoBCIEs. Thus the provision of this feature will not necessarily requireany major modifications of the already existing setup signallingmechanism.

The calling user equipment MS A may also send a “speech first”indication. The “speech first” indication is preferably transparent forthe network 10. Instead, the indicator is intended to be used by thecalled user equipment MS B only. According to a possibility the knownUser-to-User Service (UUS) is used for the signalling of the indicatorfrom the calling user equipment MS A to the called user equipment MS B.The User-to-User Service (UUS) is a standard feature that is alreadyimplemented in network elements of a modern communication system.

The indication can be e.g. a text command like “Speech”, a flag or anyother appropriate indicator that can be interpreted by the called partyuser equipment MS B. What is essential is that the called user equipmentMS B can interpret the indicator to be able to determine the mode thatshall be used for the communication. More precise examples ofappropriate indicators, possibilities to signal the indicator andsubsequent operation will be given later with references to thesignalling flow charts of FIGS. 3 to 5.

After the called user equipment MS B has received the indicator, it maysend an acknowledgement thereof and initiate a procedure for the setupof its end leg into the speech mode. The two user equipment may thencommunicate in the speech mode via the network.

As explained above, a possibility for a multimedia mode was reservedduring the setup procedure. Should the users wish to change to themultimedia mode, the change can be initiated by signalling anappropriate indicator from one user equipment to another. This can beaccomplished in the direction from the user equipment MS A to the userequipment MS B or vice versa. After the other one of the user equipmenthas received the indicator is activates a procedure for changing themode from speech to multimedia at its leg. After both end legs have beenmodified, the communication continues in the multimedia mode. It may berequired in some applications that the communication path between theend legs is also modified, although this is not the preferred option.

The following will give with reference to FIGS. 3 to 5 more detailedexamples of the signalling of information between the two userequipment. In the example the MS A is assumed as being the originatinguser and the MS B is assumed as being the terminating user. Thecommunication path via the network is shown to include three separatecontroller entities. These will be referred to as originating exchange1, transit exchange 3, and terminating exchange 2.

According to a possibility shown in FIG. 3 the indication can be sentalready in SETUP Initial Address Message (IAM) using the so called UUSservice 1. The UUS service 1 refers to a user to user signalling servicethat can be used when signalling call setup messages.

The IAM is passed through the exchanges 1, 3 and 2. The called userequipment MS B then receives the SETUP (IAM) message containing theUDI/RDI request. The reception of a SETUP message as such is an existingfeature of the ISUP and/or the GSM/UMTS, and will thus not be explainedin any greater detail. After reception the MS B may send anacknowledgement in an appropriate message. For example, messages such as‘ALERTING’, ‘Address Complete Message’ (ACM) or ‘CONNECT Answer Message’(ANM) may be forwarded to the calling user equipment MS A.

The call is then set up as a speech call, as was indicated by the SETUPmessage. However, the connection in the intermediate network may use aUDI/RDI transmission without compression to facilitate an easier swapfrom speech mode to UDI/RDI Multimedia mode, should this be required.

According to a possibility, when the called terminal MS B receives a“speech” indication, it consequently responds to the SETUP IAM with twoBCIEs, such as ‘Speech’ and ‘Multimedia’. The BCIEs may be transportedin this order so that the call will start with speech. The receivinguser equipment MS B may also acknowledge receipt of the initial speechindication from the calling user equipment MS A (using e.g. the abovementioned UUS mechanism). Thus the called user equipment MS B may alsoreserve the possibility to swap the modes later, if required. The calleduser equipment MS B may also indicate by means of the 1^(st) BCIE whichmode to use in the start of the call.

According to an alternative embodiment, the called user equipment MS Bmay respond to the setup messages with a “UDI/RDI first” (i.e. UDI/RDIMultimedia BCIE and a Speech BCIE in this order) and initiate amodification to speech (between itself and the serving network) later,e.g. immediately after the SETUP.

It is possible that the calling user equipment MS A gets a negativeacknowledgement to the “speech” request or does not get anacknowledgement at all. For example, the called terminal or theintermediate network does not support the used signalling mechanism,e.g. the UUS. The calling user equipment MS A may then initiate amodification to UDI/RDI Multimedia (between itself and the servingnetwork). A multimedia call would then result between the two userequipment.

It is also possible to invoke UUS service 2 in SETUP Initial AddressMessage (IAM) and use the UUS service 2 to convey the indication and theacknowledgement messages in between ALERTING(ACM) and CONNECT(ANM) in aUSER INFORMATION(USR) message (this is a User-to-user informationmessage). In this case the called user equipment MS B may respond to thesetup message with a “UDI/RDI first” (i.e. UDI/RDI Multimedia BCIE and aSpeech BCIE in this order) and initiate a modification to speech(between itself and the serving network) later, e.g. immediately afterthe SETUP.

As shown by FIG. 4 a, it is also possible to invoke a UUS service 3 inorder to communicate indications between the two user equipment. Withthe UUS service 3 a swap from the UDI mode to speech mode would happenas a first thing during the active phase of the call. That is, eventhough the call is setup in a multimedia mode it is immediately changedinto speech mode, and then later on, if required, changed “back” to themultimedia mode.

The UUS service 3 may be invoked in SETUP(IAM) or, as shown by FIG. 4 a,after the active call phase is reached using the so called FacilityRequest Message and Facility Accepted Message (FAR and FAA) of the ISUP.The indication of the mode and possible acknowledgements may then beconveyed with a USER INFORMATION(USR) message in the beginning of theactive call state.

Instead of the UUS mechanisms it is possible to use an ApplicationTransport Mechanism (APM) with an appropriate APM user application. TheAPM is a standard ISUP signalling mechanism, and is thus not describedin any greater detail herein.

The network apparatus such as a MSC (or MSS) may convert the BCIEs fromthe calling party MS A for the ISUP/BICC and forward them towards thecalled party MS B. The ISUP Fallback facility, as defined e.g. in ITU-TQ.764, may be requested.

After the indication of the possibility for at least one further mode issuccessfully communicated between the two user equipment, the userequipment may change i.e. swap between these modes. The following willdescribe possible procedures for a swap from speech to a Multimedia orvice versa during a call.

As shown by FIGS. 4 b and 5, a user may activate his/her user equipmentMS A to send a “swap to multimedia” (or “swap to speech”) indication.The indication is preferably transparent to the intermediate networkapparatus 1 to 3 and is meant only for the other party of the connection(MS B). As above, the User-to-User Service (UUS) may be used for thesignalling.

The indication can be e.g. a text message or command, a flag and so on.A UUS service 3 may have been invoked already in the SETUP(IAM), orduring the active call phase with a FACILITY(FAR & FAA) message. Afterinvocation UUS service 3 can be used in an active phase of a call toconvey the swap indications and acknowledgements e.g. by a USERINFORMATION(USR) message. As above, an alternative to the use of the UUSmechanism is to use APM mechanism with a suitable APM user application.

The called user equipment MS B receives the “swap to multimedia/speech”indication and, consequently, initiates a modification from Speech modeto UDI/RDI Multimedia mode or from Multimedia mode to Speech mode. Themodification is initiated by the user equipment and may only concern theleg between the user equipment MS B and an element of the servingnetwork, such as the serving exchange 2. The user equipment MS B mayalso acknowledge the “swap to multimedia/speech” indication to the userequipment MS A using e.g. the above mentioned UUS or the userinformation message.

The user equipment MS A receives the acknowledgement and, consequently,initiates a modification from speech to UDI/RDI Multimedia or multimediato speech between itself and the serving network.

Thus the connection at both end legs is modified at the initiative ofthe respective user equipment MS A and MS B. As mentioned above, theconnection in the intermediate network may all the time use a UDI/RDItransmission without compression to make a possible later swap toUDI/RDI Multimedia easier. However, it shall be appreciated that this isnot a necessity, and that the intermediate leg may also be modified insome applications.

If the user equipment MS A gets a negative acknowledgement to the “swap”request or does not get an acknowledgement at all (i.e. MS B or theintermediate network does not support the used signalling mechanism,e.g. the UUS), the user equipment MS A stays in the current mode.

If the UUS is to be used, a user equipment such as a mobile stationand/or an ISDN terminal shall support the swap feature by being capableof generating and recognising UUS “swap” messages.

According to an alternative to the above described solution whereinsignalling was carried between the user equipment, it is possible toprovide a network oriented solution for the swapping between thedifferent modes. This will be described below with reference to theflowchart of FIG. 6.

When a calling user equipment MS A wants the call to start with speech,but reserves the possibility to swap to UDI/RDI Video/Multimedia laterduring the call, it may send two BCIEs (Speech BCIE and UDI/RDIMultimedia BCIE in this order) in the SETUP message.

A controller entity 1 such as the MSC Mobile services Switching Centreor a MSC Server (MSS) may then convert the BCIEs for ISUP/BICC andforward these to another network element, and more particularly towardsto a corresponding network element 2 serving the called user equipmentMS B.

The controller entity serving the MS A sends also a “speech” indicationwhich is transparent to the intermediate network apparatus and is meantfor the corresponding network element 2 serving the called userequipment MS B. For example, the User-to-User Service (UUS) can be usedfor this purpose, but such that the message is not sent by the actualuser and to another user but between the two serving network elements 1and 2. An alternative to the UUS mechanism is the APM mechanism with asuitable APM user application.

The network element 2 serving the called user equipment MS B receivesthe SETUP (IAM) with the UDI/RDI request. The network element 2 receivesalso a “speech first” indication. The serving network element 2 mayconsequently forward the SETUP (IAM) with two BCIEs, i.e. Speech andMultimedia and in this order, towards the called user equipment MS B forsetup of the call in the speech mode. The BCIEs may need to be convertedfrom ISDN to 3GPP format.

The called user equipment MS B may respond to the SETUP with two BCIEs,Speech and Multimedia in this order, to start with speech. The networkelement 2 serving the called party MS B acknowledges the “speech”indication to the network element 1 serving the calling party userequipment MS A. The above discussed UUS may be used also for thispurpose.

The call is then set up as a speech call. However, the connection in theintermediate network may use a UDI/RDI transmission without compressionto make a possible later swap to UDI/RDI Multimedia easier.

If the network element 1 serving the calling user equipment MS A gets anegative acknowledgement to the “speech” request or does not get anacknowledgement at all, the network element 1 may initiate amodification to UDI/RDI Multimedia (between itself and MS A).

When a user of either the calling or the called user equipment wants toswap from Speech to Multimedia or vice versa during the call, the usermay initiate the swapping procedure at his/her equipment. E.g. anIn-Call Modification procedure may be used in here, this being anexisting 3GPP feature.

In accordance with an embodiment a network element (e.g. 1) serving auser equipment (e.g. MS A) initiates the In-Call Modification and thusstarts the modification procedure between itself and the user equipment.The network element may then send a “swap to multimedia” (or “swap tospeech”) indication which is transparent to the intermediate network andis meant for a network element (e.g. 2) that serves another userequipment (e.g. MS B). As above, this may be accomplished by means of aUUS (User-to-User Service) or APM mechanism with a suitable APM userapplication.

When said other network element serving the other user equipmentreceives the “swap to multimedia” (or “swap to speech”) indication, itmay consequently initiate a modification from Speech to UDI/RDIMultimedia or vice versa on the leg between itself and said other userequipment.

The network element serving the other user equipment (e.g. MS B) mayacknowledge the “swap” request to the network element serving therequesting user equipment. The In-Call Modification procedure is thenfinished at this user equipment (e.g. MS A). The connection at both endlegs is then modified.

As above, the connection in the intermediate network may not need anymodification as it may have been set up to use a UDI/RDI transmissionall the time without compression to make a possible later swap toUDI/RDI Multimedia easier.

If e.g. a network element 1 serving a user equipment MS A gets anegative acknowledgement to the “swap” request or does not get anacknowledgement at all, the network element 1 serving the user equipmentMS A may reject the In-Call Modification and the connection stays in itscurrent mode.

According to a possibility the controller entity 1 serving the userequipment MS A communicated with the called user equipment MS B insteadof the network element 2 serving the called user equipment MS B. Thismay be needed e.g. in a so called “mobile-to-ISDN-terminal” case.

Signalling between a user equipment and a network element may also berequired e.g. in instances wherein one party of a call is served by apacket switched (PS) network while another party B is served by acircuit switched (CS) network, see FIG. 7. In FIG. 7 signalling of therequired indicators occurs between an interworking network element 4 anda user equipment MS A (or the network element serving the userequipment) in communication via a circuit switched environment 10. Theother party of the call is connected to a packet switched communicationenvironment 20, for example to one operating in accordance with theInternet Protocol (IP) or Session Initiation Protocol (SIP).

It is noted that the above disclosed solution is applicable also in acase wherein more than two user equipment are involved in the call, forexample in the case of a conference call. User terminals and theconference bridge may swap in a similar manner between operating modes.It is also possible that some of the connections are in the speech modeand some in video/multimedia mode.

It should be appreciated that while embodiments have been described inrelation to user equipment such as mobile stations, other embodimentsare applicable to any other suitable type of user equipment.

This embodiment has been described in the context of GSM based systems.This invention is also applicable to any other communication systems.

It shall also be appreciated that the principles described withreference to FIGS. 2 to 5 can also be used for provision of othercontrol features. Thus any control instructions may be signalled via alink between a first user equipment and a second user equipment via acommunications network where after in at least one of the user equipmentmay initiate a procedure for provision of control operations inaccordance with said instructions. The initiation may occur e.g. suchthat said user equipment sends a control procedure activation signal tothe network.

It is also noted herein that while the above describes exemplifyingembodiments of the invention, there are several variations andmodifications which may be made to the disclosed solution withoutdeparting from the scope of the disclosure as defined in the appendedclaims.

What is claimed is:
 1. A method in a communication system, the methodcomprising: initiation of a procedure for setting up a communicationlink between a first user equipment and a second user equipment via acommunications network; signalling between the first user equipment andthe second user equipment information regarding at least two modes ofcommunication that can be used for a communication via the communicationlink; signalling between the first user equipment and the second userequipment an indicator regarding changing a mode used for thecommunication to another mode of the at least two modes to be used forthe communication, wherein the signalling is user-to-user service duringan active phase of the communication.
 2. The method of claim 1 furthercomprising initiating in the first user equipment a procedure forchanging the mode during the communication in accordance with theindicator, wherein the first user equipment communicates with thecommunications network via a wireless interface.
 3. The method of claim2, wherein the indicator is a flag.
 4. The method of claim 1, whereinthe indicator is a text message.
 5. The method of claim 4, wherein thetext message is “swap to speech.”
 6. The method of claim 1, wherein theindicator is a command.
 7. The method of claim 1, wherein the indicatoris a flag.